HELENA, Mont. (AP) — Montana Lt. Gov. John Walsh will run for the U.S. Senate in 2014, his campaign said Thursday, giving Democrats the high-profile candidate they’ve been scrambling for in a bid to keep the seat they’ve held for decades.

Walsh plans to tell supporters Thursday morning that he will run for the office that has been the focus of a great deal of speculation since Sen. Max Baucus announced earlier this year that he will retire at the end of 2014.

An advance copy of the announcement provided to The Associated Press said the 52-year-old former Montana National Guard commander is running because Washington needs more leaders with a “sense of duty” to do what’s right.

“Too many lawmakers back in Washington put their own agendas ahead of their responsibility to their constituents and to all Americans,” Walsh’s statement said. “They put their political party, and their personal careers ahead of the people they are supposed to be representing. They’ve forgotten their obligations and responsibilities.”

The up-in-the-air Montana race could help determine control of the Senate.

Republicans, who like their chances in the GOP-leaning state, need to pick up six seats to recapture the Senate majority and are trying to take advantage of geography and history in their quest.

Democrats must defend 21 seats, including seven in largely rural states that Obama lost in 2012, and the party that controls the White House typically loses seats during the midterm elections of a second-term president.

Baucus shocked Montana politics when he announced in April he would not seek a seventh term despite a large campaign war chest and no serious announced opposition. Baucus, who in recent years has bemoaned increased polarization in Washington, said he was walking from chairmanship of the Senate Finance Committee and high-ranking seniority so that he could enjoy a life outside of politics for the first time since the early 1970s.

The announcement created a scramble for candidates on both sides, and a free-for-all for the first open Senate seat in the state since 1978.

Several statewide elected Democrats — and the man once assumed to be the front-runner in the 2014 race, former Gov. Brian Schweitzer — have spurned recruitment efforts.

Former Lt. Gov. John Bohlinger — a Republican turned Democrat — has said he is considering it. And a political unknown and former San Francisco banker, Dirk Adams of Wilsall, has said he will mount a campaign.

Many Republicans expect U.S. Rep. Steve Daines will enter the race as their front-runner. Daines has been raising money consistent with a Senate run, and has said he could announce his decision fairly soon.

Former Gov. Marc Racicot, who used to chair the Republican National Committee, rejected a run of his and encouraged Daines to enter the race.

Two other low-profile Republicans have already said they are running, current state Rep. Champ Edmunds of Missoula and Kalispell air traffic manager David Leaser.

Walsh, the former adjutant general who has said he never considered a run before Schweitzer bowed out, enters the race with just one election under his belt. He won a tight race last year as Gov. Steve Bullock’s running mate.

He has two grown children with his wife, Janet, and a grandchild.

Walsh, a native of the Democratic stronghold of Butte, touted his long military career and promised to put politics aside in the Senate.

“I’m not a politician. I’m a soldier. I’m a fourth-generation Montanan from Butte,” a message prepared for supporters said. “For all our children and grandchildren, Montana deserves leaders who will live up to their obligations, put service ahead of self, and have the courage to make the tough decisions while protecting the vulnerable.”